Problem: Solve for $k$, $- \dfrac{3k + 9}{3k + 7} = 7$
Multiply both sides of the equation by $3k + 7$ $ -(3k + 9) = 7(3k + 7) $ $-3k - 9 = 21k + 49$ $-9 = 24k + 49$ $-58 = 24k$ $24k = -58$ $k = -\dfrac{58}{24}$ Simplify. $k = -\dfrac{29}{12}$